https://www.theguardian.com/music/2018/mar/17/kylie-minogue-live-review-cafe-de-paris-golden-album
Gig review in The Guardian. I'm not a fan myself, but there are decriptions of the other album tracks for anyone who is.

The song is "co-written" by Hillary Lindsey, one of the biggest songwriting names to come out of the Nashville scene this past decade, and who has been the force behind almost all of Carrie Underwood's career. There's no way Gaga would've spent the big bucks on her without expecting Lindsey to do the heavy lifting and deliver a hit. Think what you want of Million Reasons the song, but it's close to being the only listenable thing on the whole Joanne album, and that's Lindsey shining through. Perfect Illusions and John Wayne are like nails on a chalkboard.
I find musical collaboration to be a really interesting thing. In Madonna's case, there's such consistency in quality no matter who she works with, as well as common lyrical patterns and phrases through various albums, that it's really clear how heavily involved she is with the writing and producing work. Whereas with Gaga, results vary wildly all over the place depending on who she works with (ie. she's not as heavily involved as she's desperate for you to believe she is). Another example is Hole (Courtney Love) - I love them, but I've always thought there's no way that Live Through This and the Celebrity Skin album are written by the same person.

I didnt think of that song @Jazzy Jan but you're absolutely right, Somebody... is one of those genuinely bitter and emotional hit songs! Maybe it was a huge hit because it had cross-generational appeal too. It had a complex emotional story to tell, I loved it the first 70 times I heard it!

I think this is the issue.
That, and the fact that there's a whole generation that are terrified of their own feelings, heavily medicated by actual medication or by numbing addictions like alcohol, overwork, tv and social media, and live in a childlike extended adolescence until they are thirty.
I was thinking the other day how genuinely bitter anger is so rare to hear in a song nowadays. My parents loved big hits like Dreams by Fleetwood Mac, just as I loved You Oughta Know by Alanis Morissette and many grunge songs. The closest that current youth can handle is focus-grouped, corporate-approved diet anger in songs like Hello by Adele or U & Ur Hand by Pink.
I think there's a new generation that is emotionally unsophisticated, and music is an artform about emotions, so spot the problem!

I've had two friends tell me in the past fortnight that they watched the doco out of curiosity and that even though they started the film feeling neutral about Lady Gaga, they finished it disliking her.
They particularly noticed the grandma song debut scene, the "everyone is leaving me" bullshit after her conversation with terminally-ill Sonja and the awkward topless meeting.

Taylor has quite a few big hits that were written entirely by herself though too - see Love Story and Mine for example. The Speak Now album was very successful too and that was written by her alone in its entirety. Even on 1989, the deluxe edition has a recording of when she first presents her Blank Space demo to Max Martin and Shellback and it sounds pretty close to the final version already, like what they contributed was fairly minor in terms of songwriting.
I just think Taylor is a thin-skinned entitled princess whose head has been absolutely done in by the backlash of recent times. This fourth song is supposed to be a love song and yet it is so defensive, uptight and focussed on her public perception still. If it were the other collaborators doing the bulk of the writing, I actually think this side to her WOULDN'T be showing as much, because it's unpleasant, unrelatable and not connecting with her fans.

This is it exactly. When popstars disappear so far up their own asses that they start singing about fame ("Applause") and non-relatable subject matter (celebrity disses), the public quickly loses interest.
I do genuinely believe that Taylor is a fantastic songwriter ("All Too Well" is one of the best break-up songs ever written), but she is thin-skinned and the change in public perception / backlash is throwing her off her game massively. She's one of these people that's been told she is special all her life and can't handle any criticism. There were signs of it way back when she got so defensive about Tina Fey's joking at the Golden Globes.